⁶. The primary reason for using broadcast and multicast is to gain channel efficiency by communicating with multiple entities via a single common message. However, the complexity of matching acknowledgments with intended message recipients at the source quickly overrides any efficiencies gained in a reliable multicast scenario. Depending on the number of channels, the number of members in the multicast group, etc., a set of unicast messages might be equally efficient for reliable communications. It really depends on where you want to handle reliability–in the networking technology transporting the message or in the application itself. We’ll talk more about reliability later.